Randomized study of postoperative chemotherapy (CT) after preoperative chemoradiation (CTRT) in locally advanced rectal cancer (LARC). Preliminary results

Postoperative adjuvant chemotherapy use in patients with stage II/III rectal cancer treated with neoadjuvant therapy: a national comprehensive cancer network analysis

PURPOSE

Practice guidelines recommend that patients who receive neoadjuvant chemotherapy and radiation for locally advanced rectal cancer complete postoperative adjuvant systemic chemotherapy, irrespective of tumor downstaging.

PATIENTS AND METHODS

The National Comprehensive Cancer Network (NCCN) Colorectal Cancer Database tracks longitudinal care for patients treated at eight specialty cancer centers across the United States and was used to evaluate how frequently patients with rectal cancer who were treated with neoadjuvant chemotherapy also received postoperative systemic chemotherapy. Patient and tumor characteristics were examined in a multivariable logistic regression model.

RESULTS

Between September 2005 and December 2010, 2,073 patients with stage II/III rectal cancer were enrolled in the database. Of these, 1,193 patients receiving neoadjuvant chemoradiotherapy were in the analysis, including 203 patients not receiving any adjuvant chemotherapy. For those seen by a medical oncologist, the most frequent reason chemotherapy was not recommended was comorbid illness (25 of 50, 50%); the most frequent reason chemotherapy was not received even though it was recommended or discussed was patient refusal (54 of 74, 73%). After controlling for NCCN Cancer Center and clinical TNM stage in a multivariable logistic model, factors significantly associated with not receiving adjuvant chemotherapy were age, Eastern Cooperative Oncology Group performance status ≥ 1, on Medicaid or indigent compared with private insurance, complete pathologic response, presence of re-operation/wound infection, and no closure of ileostomy/colostomy.

CONCLUSION

Even at specialty cancer centers, a sizeable minority of patients with rectal cancer treated with curative-intent neoadjuvant chemoradiotherapy do not complete postoperative chemotherapy. Strategies to facilitate the ability to complete this third and final component of curative intent treatment are necessary.

Point: short-course radiation therapy is preferable in the neoadjuvant treatment of rectal cancer

There are 2 types of neoadjuvant radiation regimens accepted as standard for resectable rectal cancer: short-course (5 × 5 Gy) radiation therapy alone with immediate surgery and long-course combined chemoradiation therapy with delayed surgery. A Polish randomized study (n = 312) and an Australian randomized study (n = 326) compared these 2 schedules. Both trials showed a lower rate of early adverse effects using a short-course radiation regimen and no differences in long-term oncologic outcomes and late toxicity rates between groups. The small number of fractions makes short-course radiation less expensive and more convenient than chemoradiation therapy. These facts indicate that short-course radiation is preferable to chemoradiation for resectable cancers. Additionally, short-course preoperative radiation with a long interval to surgery is a valuable option for patients unfit for chemotherapy, with unresectable cancer or with a small tumor that is amenable to local excision. Moreover, short-course radiation enables the intensification of both radiotherapy and chemotherapy in patients with metastatic rectal cancer with potentially resectable synchronous metastatic disease.

Does adjuvant fluoropyrimidine-based chemotherapy provide a benefit for patients with resected rectal cancer who have already received neoadjuvant radiochemotherapy? A systematic review of randomised trials

BACKGROUND

The results of the recently published large European randomised study in rectal cancer (European Organisation for Research and Treatment of Cancer 22921 trial) do not support current guidelines recommending postoperative chemotherapy for patients who have previously undergone preoperative radiochemotherapy or radiotherapy [radio(chemo)therapy]. To evaluate this discrepancy further, a systematic review of relevant randomised trials was undertaken.

MATERIALS AND METHODS

A systematic literature search was carried out in order to identify randomised studies exploring adjuvant chemotherapy against observation in patients with rectal cancer previously treated with preoperative radio(chemo)therapy.

RESULTS

A statistically significant benefit of adjuvant chemotherapy was not found in any of the four relevant randomised trials. Non-protocolised subgroup analysis of one study indicated a beneficial effect of adjuvant chemotherapy for high rectal tumours and for patients downstaged to ypT0-2N0 but no effect for low-lying rectal tumours. However, the body of evidence indicates that patients downstaged after radio(chemo)therapy to ypT0-2N0 disease are not candidates for testing adjuvant chemotherapy in future trials due to the considerable over-treatment anticipated by this manoeuvre.

CONCLUSIONS

To resolve the issue in question, a meta-analysis of relevant studies is required, and new trials should be launched to explore new drug combinations against observation. Currently, delivery of adjuvant chemotherapy in patients undergoing preoperative radio(chemo)therapy is not evidence based.

Circumferential resection margin as a prognostic factor in rectal cancer

BACKGROUND

This study examined the prognostic impact of the circumferential resection margin (CRM) in patients with rectal cancer treated by total mesorectal excision (TME) with or without radiotherapy.

METHODS

A national population-based rectal cancer registry included 3196 patients with known CRM status between 1993 and 2004. Some 90.5 per cent of the patients had surgery alone and 9.5 per cent had preoperative radiotherapy. Patients who did not have TME, those in whom the CRM was not measured, patients with intraoperative bowel or tumour perforation and those who received postoperative radiotherapy were excluded.

RESULTS

Five-year local recurrence, distant metastasis and overall survival rates were 23.7, 43.9 and 44.5 per cent respectively for patients with a CRM of 0-2 mm, compared with 8.9, 21.7 and 66.7 per cent respectively for those with wider margins. A CRM of 2 mm or less had an impact on the prognosis of T2 and T3 tumours located 6-15 cm above the anal verge, but not on lower tumours. CRM also had a prognostic impact on the three endpoints in patients who received preoperative radiotherapy, but with less precision.

CONCLUSION

A CRM of 2 mm or less confers a poorer prognosis and patients should be considered for neoadjuvant treatment.

Is there a role for radiotherapy in operable rectal cancer?

Most patients presenting with rectal cancer will have "operable" disease. The main aim in treating these patients is to achieve complete surgical resection while minimising the rate of local recurrence. The use of radiotherapy has been shown to decrease local recurrence rates and the evidence suggests that this should be used preoperatively. Here we summarise the important trials both before and after the introduction of mesorectal excision. We highlight some of the important issues, including treatment-related toxicity and patient selection for preoperative treatment.

A phase I-II study of weekly oxaliplatin, 5-fluorouracil continuous infusion and preoperative radiotherapy in locally advanced rectal cancer

BACKGROUND

Oxaliplatin (OXA) significantly enhanced the antitumour activity of 5-fluorouracil (FUra) in patients with advanced colorectal cancer and displayed radiosensitising properties in preclinical studies. This study was thus performed to test the feasibility, identify the recommended doses (RDs) and explore preliminarily the clinical activity of weekly OXA and infused FUra combined with preoperative pelvic radiotherapy.

PATIENTS AND METHODS

Forty-six patients with recurrent or locally advanced (cT3-4 and/or N+) adenocarcinomas of the mid-low rectum were treated with escalating doses of OXA (25, 35, 45, 60 mg/m2, weekly for 6 weeks) and FUra (200-225 mg/m2/day, 6-week infusion) concurrent to preoperative pelvic radiotherapy (50.4 Gy/28 fractions). The RDs for the phase II part of the study were immediately below the level resulting in dose-limiting toxicities in more than one third of the patients, or corresponded to the last planned dose level.

RESULTS

In the escalation phase, dose-limiting toxicities only occurred in one patient at the fourth level and one of six patients treated at the last planned dose level (grade III diarrhoea). OXA 60 mg/m2 and FUra 225 mg/m2/day are therefore the RDs for the regimen. Among 25 patients globally treated at these doses (phase II part), the incidence of grade III diarrhoea was 16% with no grade IV toxicity. Neurotoxicity did not exceed grade II (12%). All patients completed radiotherapy and were operated on as scheduled. Twenty-one of 25 patients had the tumour down-staged after chemoradiation with seven (28%) pathological complete responses and 12 (48%) residual tumours limited to ypT1-2N0.

CONCLUSIONS

Weekly OXA, at doses potentially active systemically, can be combined with full-dose, infused FUra and radiotherapy. Given the low toxicity and promising activity, this regimen is being compared to standard FUra-based pelvic chemoradiation in a randomised study.